Kubelet configuration: Maximum pods flag is miscalculated when using Amazon VPC CNI

[liranp]

Nodeup takes into account the first instance type from the Instance Group spec when the max-pods is calculated. This leads to a miscalculated value when using multiple instance types.

This PR fixes the issue by querying the EC2 instance metadata service to find out the actual instance type and maintains backward compatibility by falling back to the Instance Group spec.

[k8s-ci-robot]

Hi @liranp. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[rifelpet]

/ok-to-test

[rifelpet]

/test pull-kops-verify-gomod

[rifelpet]

/lgtm

[rifelpet]

/test pull-kops-verify-generated

[rifelpet]

/lgtm

[gjtempleton]

/lgtm

[mikesplain]

Thanks @liranp!

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liranp, mikesplain

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